Social connection is the strongest protective factor for depression
Researchers from Massachusetts General Hospital (MGH) have identified a set of modifiable factors from a field of over 100 that could represent valuable targets for preventing depression in adults. In a study published in The American Journal of Psychiatry, the team named social connection as the strongest protective factor for depression, and suggested that reducing sedentary activities such as TV watching and daytime napping could also help lower the risk of depression.
Karmel Choi, PhD“
Depression is the leading cause of disability worldwide, but until now researchers have focused on only a handful of risk and protective factors, often in just one or two domains. Our study provides the most comprehensive picture to date of modifiable factors that could impact depression risk.
”
Department of Psychiatry, Massachusetts General Hospital
To that end, researchers took a two-stage approach. The first stage
drew on a database of over
100,000 participants in the UK Biobank -- a world-renowned cohort study of adults –
to
systematically scan a wide range of modifiable factors that might be associated with
the risk of
developing depression, including social interaction, media use, sleep patterns,
diet, physical
activity, and environmental exposures. This method, known as an exposure-wide
association scan
(ExWAS), is analogous to genome-wide association studies (GWAS) that have been
widely used to
identify genetic risk factors for disease. The second stage took the strongest
modifiable
candidates from ExWAS and applied a technique called Mendelian randomization (MR) to
investigate
which factors may have a causal relationship to depression risk. MR is a statistical
method that
treats genetic variation between people as a kind of natural experiment to determine
whether an
association is likely to reflect causation rather than just correlation.
This two-stage approach allowed the MGH researchers to narrow the field to a smaller
set of
promising and potentially causal targets for depression. “Far and away the most
prominent of
these factors was frequency of confiding in others, but also visits with family and
friends, all
of which highlighted the important protective effect of social connection and social
cohesion,”
points out Jordan Smoller, MD, ScD associate chief for research in the MGH
Department of
Psychiatry, and senior author of the study. “These factors are more relevant now
than ever at a
time of social distancing and separation from friends and family.” The protective
effects of
social connection were present even for individuals who were at higher risk for
depression as a
result of genetic vulnerability or early life trauma.
On the other hand, factors associated with depression risk included time spent
watching TV,
though the authors note that additional research is needed to determine if that risk
was due to
media exposure per se or whether time in front of the TV was a proxy for being
sedentary.
Perhaps more surprising, the tendency for daytime napping and regular use of
multivitamins
appeared to be associated with depression risk, though more research is needed to
determine how
these might contribute.
The MGH study demonstrates an important new approach for evaluating a wide range of
modifiable
factors, and using this evidence to prioritize targets for preventive interventions
for
depression. “Depression takes an enormous toll on individuals, families, and
society, yet we
still know very little about how to prevent it,” says Smoller. “We’ve shown that
it’s now
possible to address these questions of broad public health significance through a
large-scale,
data-based approach that wasn’t available even a few years ago. We hope this work
will motivate
further efforts to develop actionable strategies for preventing depression.” The
study’s
two-stage approach could also be used to inform the prevention of other health
conditions.